Q. Lu | Missing Scalars at the Cosmological Collider

Parallel Talk | Cosmology from Home 2021

Talk title:
Missing Scalars at the Cosmological Collider
Speaker:
Qianshu Lu

Talk abstract:
The cosmological collider program utilizes the uniquely high energy scale of inflation and searches for the existence of new particles through their imprints on large-scale density perturbations. Despite their copious production, scalars that are much lighter than Hubble during inflation are difficult to detect directly in the cosmological collider and act as "missing scalars". In this talk, we show that if such a light, missing scalar interacts with a heavy scalar that couples to the inflaton, the spatial variation of the light field can act as a space-dependent mass correction to the heavy field. This space-dependent mass correction modifies the oscillatory signature of the heavy scalar in a distinctive way, making the missing scalar potentially observable at the bispectrum level.